What is a two-color mold? How to design two-color mold
Part 1: Principles of two-color injection molding and understanding of injection molding machines
Two-color molds usually have two molds, one half is installed on the fixed plate of the machine, and the other half is installed on the rotating plate. The male molds of the two molds are exactly the same, but the primary female mold and the secondary female mold are different. When the first After the plastic injection molding of the first color is completed, the male and female molds are opened. The male mold takes the product once and rotates 180 degrees to reach the position where the second color injection molding is performed. A second injection is performed to obtain a two-color part. In this cycle, each During the molding cycle, there will be one mold of primary products and secondary products.
Part 2 Application of two-color mold
Choosing a two-color mold generally involves the following situations.https://solidcomould.com/product/plastic-electrical-junction-box-injection-mould-sc01/
- Product function requirements. For example, power switches, mobile phone buttons, keyboard indicators, car switches, etc. require that the LED part can transmit light
Part 3 Mold Design Techniques - Shrinkage rate Generally speaking, the shrinkage rate of a two-color mold depends on the primary material. The secondary material and the primary material should have the same shrinkage rate. For example, the primary material is ABS (shrinkage is usually 0.5%), and the secondary material is TPE ( Shrinkage is usually 1.8%). When designing a two-color mold, all 0.5% should be used because the primary material has already supported the product outline and the secondary material will not shrink more.
Part 4 Two-color mold with special structurehttps://doi.org/10.1016/j.polymertesting.2023.107982 - Seesaw structure
This type of structure is mainly used on numeric keyboards, such as 0, 4, 6, 8, 9 closed numbers and A, B, D, O, P, Q, R, closed letters. Only the seesaw structure is used, quadratic Material will flow into the closed area - Medium plate mold
As we all know, the two male molds of the two-color mold are exactly the same. However, what should we do if the structure of the product requires that the two male molds are also different? Please think of the middle plate mold! The working principle of the middle plate mold: Injection Molding During molding, the two male molds do not move. After completing the first injection molding, the injection molding machine first takes out the middle plate, then rotates the middle plate 180 degrees, and then performs secondary molding. In this way, the first and second parts of the middle plate can be into different shapes to achieve our intended design purpose.
Part 5 Some common techniques
Mold:
① First load the second mold (male and female molds together) and lock the mold slightly to open the mold, then lock the male and female molds a little again, and then lock the second male and female molds (to prevent the first and second molds from opening). not on the same level).
② Rotate the male mold once and the male mold will lock the second female mold; once the female mold will lock the second male mold.
③ Rotate the male mold again and if the male mold and the female mold can be closed once, it is OK.
Items to note when repairing the lower mold:
① When repairing the lower male mold, you must close it with the secondary female mold and then lock it (there is a certain gap between the guide post and the hole).
② Next time the female mold is repaired: directly close it with the male mold to lock it. Repair the secondary female mold: lock it slightly after upper molding, loosen the lock of the male mold, tighten the primary female mold and the male mold, lock the secondary female mold and the male mold after they are closed, and then rotate the male mold. Close the primary male mold and the secondary female mold and lock the male mold. After closing the primary female mold and the secondary male mold, lock the female mold (once) and then rotate the female mold and the male mold once to close them.
